1. Field of the Invention
The present invention relates to a CATV system equipped with a digital broadcasting receiving unit and a bidirectional remote controller.
2. Description of the Background Technology
The BS digital broadcasting and CS digital broadcasting of recent years have been multi-channeled, and data broadcasting service such as electronic program guides (hereinafter, “EPGs”) used so that a viewer can select a desired program from many broadcast programs, weather forecast and news besides the programs has been in practical use.
Further, in the CATV system, the programs of the BS digital broadcasting and CS digital broadcasting have been remultiplexed, and pay-TV programs such as video-on-demand broadcasting (hereinafter, “VOD broadcasting”) have been broadcast. Thus, it has become possible for viewers to watch various broadcastings by carrying out a remote control while viewing a television screen.
Such a prior art CATV system is described with reference to FIG. 5. FIG. 5 is a block diagram showing a construction of the prior art CATV system. In FIG. 5, identified by 1 is a digital broadcasting transmitting unit, by 2 a CATV transmission line, by 3 a digital broadcasting receiving unit (hereinafter, “STB”), by 4 a television receiver and by 5 a bidirectional remote controller for conducting a desired operation to the STB 3.
The digital broadcasting transmitting unit 1 multiplexes contents of general broadcast programs, data broadcasting services such as EPGs, and the VOD broadcastings into a plurality of transport streams, and each transport stream is transmitted as a carrier wave to the STB 3 via the CATV transmission line 2 after being digitally modulated.
The STB 3 is provided with a transmission function of separating a target content from the multiplexed contents and transmitting it to the television receiver 4. A viewer operates the bidirectional remote controller 5 to control the STB 3, whereby a desired program or various pieces of service information can be watched on the television receiver 4.
Further, a digital broadcasting receiving system disclosed in Japanese Unexamined Patent Publication No. H10-271359 is, for example, known as a system having the same functions as the above CATV system. In this digital broadcasting receiving system, electronic program information obtained by a digital broadcasting receiving unit is displayed on a display of a bidirectional remote controller and the digital broadcasting receiving unit is controlled based on this display.
However, in the former CATV system, it was not possible to simultaneously receive a general broadcast program and a broadcasting of a different channel not related to this general broadcast program, i.e., a VOD broadcasting, if the STB 3 is equipped with only one tuner. Thus, if the viewer tries to watch the VOD broadcasting, he is obliged to select a channel of the service information (list of titles of movies, what's new information and screen used to purchase the movie, etc.) set for the VOD broadcasting, a channel of a movie preview broadcast screen or the like and to switch from the general broadcast program being watched to the display screen of the television receiver 4.
Further, if the STB 3 is equipped with a plurality of tuners, it is possible to simultaneously display the screen of the VOD broadcasting of a channel different from the broadcast program being watched as a picture-in-picture screen within the screen of the television receiver 4 or to display it on the display of the bidirectional remote controller 5. However, the service information of the VOD broadcasting having an information capacity corresponding to the general broadcast program is difficult to confirm when being displayed on the picture-in-picture screen or on the display of the bidirectional remote controller 5. As a result, the display screen of the television receiver 4 needed to be switched to a similar state by, for example, switching the general broadcast program being watched to the display on the picture-in-picture screen. These points also hold true for the latter digital broadcasting receiving system, which has similar problems accordingly.